I also know that there were at least 2 Hurricane squadrons based in France during the Battle of France which were using 100 octane fuel.
Taken from another post I made here;
"The 1st combat reports of a 12 lb boost being used in France are from 18th May 1940 with F/Lt I. R. Gleed of 87 Squadron (based in Lille) and S/L E. M. Donaldson and P/O John Bushell both of 151 Squadron (based in Vitry).
http://www.wwiiaircraftperformance.o...ed-18may40.jpg
http://www.wwiiaircraftperformance.o...e/bushell.html
http://www.wwiiaircraftperformance.o...dn-18may40.pdf "